I've installed Xfce/Gnome/Mate on new computers for senior family members and they don't even notice half the time. They just think it's a new version of Windows or Mac.

In age ranges from 40-72+.

The "vast majority" you speak of probably mostly use a web browser and a mail client, so their interactions with the actual OS are minimal.

Sometimes I get calls about digital cameras (or phones nowadays), so then I either go there and set it up, or have them open external access in some manner (usually Teamviewer, because it's easier for them). But this is rare, and of course I don't mind talking to them and helping them anyway.

And it would also happen when they used Windows.